In the weeks before the 2011 Brisbane and Ipswich flood, Brisbane dam engineers were preoccupied about "adverse media effects" and "major embarrassment" if water was unnecessarily released from Wivenhoe Dam, a court has heard.

On Tuesday the court heard Seqwater, operator of the Wivenhoe and Somerset dams, ignored its own operating manuals and acted too slowly, despite weather warnings.

Representing the plaintiffs, barrister Julian Sexton told the court Seqwater was concerned about releasing water ahead of the weather event because it might result in adverse and embarrassing media coverage if the forecast rain did not arrive.

The information, revealed in an email between a Seqwater flood engineer and its dam operations manager in December 2010, also suggested the company could be accused of "wasting water".

"Major embarrassment is not one of the objectives in the manual nor is concern about media reporting and public relations," Mr Sexton said.